[1] Univ Florida, Coll Med, Dept Radiat Oncol, Gainesville, FL USA
[2] Inst Oncol, Dept Radiat Oncol, Ljubljana, Slovenia
[3] Emory Univ, Sch Med, Dept Radiat Oncol, Atlanta, GA USA
[4] Univ Groningen, Dept Radiat Oncol, Univ Med Ctr Groningen, Groningen, Netherlands
[5] Inst Invest Sanitaria Principado Asturias, Oviedo, Spain
[6] ISCIII, CIBERONC, Oviedo, Spain
[7] Univ Oviedo, Inst Univ Oncol Principado Asturias, Oviedo, Spain
[8] Univ Hong Kong, Dept Clin Oncol, Hong Kong, Peoples R China
[9] Univ Hong Kong, Shenzhen Hosp, Hong Kong, Peoples R China
[10] Univ Udine, Sch Med, Udine, Italy
[11] Prince Wales Canc Ctr, Dept Radiat Oncol, Sydney, NSW, Australia
[12] Univ Michigan Med, Dept Radiat Oncol, Ann Arbor, MI USA
[13] H Lee Moffitt Canc Ctr & Res Inst, Dept Radiat Oncol, Tampa, FL USA
[14] St Vincents Hosp, GenesisCare Radiat Oncol Ctr, Melbourne, Vic, Australia
[15] Int Head & Neck Sci Grp, Padua, Italy